[amsat-bb] 70 cm Lindenblad progress - notable support structure for parasitic elements

[Curt Laumann]

Hi Chris,

I really have to chuckle at this discussion!!!  I grew up in MN, but now
live in Tucson... what a contrast.  I see squirrels maybe a few times a
year on my Tucson property, but the Arizona UV is obviously brutal.  One of
my friends (K7RJ) printed out a PLA part to use on an outside mast.  It
lasted about six months (outside in direct sun) and started to show signs
of significant deformation.

 By the way, the "cold" water here in Tucson (at my house) doesn't get cold
to the touch until (literally) October.  :)

Curt / K7ZOO

On Wed, Sep 23, 2020 at 1:09 PM Chris Thompson <g0kla at arrl.net> wrote:

> This looks great.  I look forward to seeing the STL and design files.
> BTW PLA held up well for 3D printed antenna parts in Brooklyn NY.  It
> might melt elsewhere, but given the melting point is about 180C and it only
> got to about 40C on my roof, the 3D printed parts were fine.  I had them up
> through winter and summer for many years.  It seems UV resistant.  While
> squirrels have access to the roof, they could not get to the 3D printed
> parts, so that was not an issue.
>
> 73
> Chris
>
> On Wed, Sep 23, 2020 at 12:33 PM E.Mike McCardel via AMSAT-BB <
> amsat-bb at amsat.org> wrote:
>
>> Curt,
>>
>> Your whole process and experimentation of these would make for an
>> interesting AMSAT Journal article.
>> If you have the time, please consider writing it up. Pictures included.
>>
>> E. Michael McCardel, AA8EM, former KC8YLD
>> Former Senior Editor for AMSAT News Service,
>> Past VP Educational Relations for AMSAT-NA
>>
>> Have you donated to get your Fox-1 Challenge Coin Yet?
>> http://www.amsat.org/?p=3275
>>
>>
>> On Tue, Sep 22, 2020 at 8:46 PM Curt Laumann via AMSAT-BB <
>> amsat-bb at amsat.org> wrote:
>>
>> > Hi All,
>> >
>> > Over the past few months I've been designing & assembling a few 70 cm
>> > Lindenblads.  The current version is shown in the attached picture (link
>> > below).  Arrow shafts are used for parasitic elements.  The shafts are
>> > bonded in place with fiberglass resin.  Rubber end caps (from McMaster)
>> > cover the shaft ends.
>> >
>> > The notable part of this design is the central structure (supporting
>> > parasitic elements) is 3D printed as *one part*.  Virtually all of the
>> > angles and spacings are achieved in the 3D printing process.  After
>> > struggling to align and bond various PVC and irrigation parts in other
>> > versions, it was a breeze to assemble this design:  one nylon machine
>> > screw, one nut, four bonding points.
>> >
>> > The design could be easily modified to accommodate 0.125 inch diameter
>> > parasitic elements as well.
>> >
>> > Regards,
>> >
>> > Curt / K7ZOO
>> > Tucson AZ
>> >
>> >
>> >
>> https://drive.google.com/file/d/1i2c6T5lZtI00KChbJuyphvvechzBvlNw/view?usp=sharing
>> > _______________________________________________
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>> Opinions
>> > expressed
>> > are solely those of the author, and do not reflect the official views of
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>> >
>> _______________________________________________
>> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
>> to all interested persons worldwide without requiring membership.
>> Opinions expressed
>> are solely those of the author, and do not reflect the official views of
>> AMSAT-NA.
>> Not an AMSAT-NA member? Join now to support the amateur satellite program!
>> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>>
>
>
> --
> Chris E. Thompson
> chrisethompson at gmail.com
> g0kla at arrl.net
>